Tonto, looks like you would be better served taking a LEFT onto W 23rd/MO 78 (item 4 on your MapQuest instructions). That will take you to 291/470, 6 lane divided, take it south (right) toward Lee's Summit. Stay on 470 and it will turn west and take you to the Grandview Triangle (not marked as such, local term, intersection of 435, 71, 470), BUT it will minimize your passage through it and keep you out of most construction. As you near the GRANDVIEW exit move to the left (inside) lane and stay there, you will exit onto a high flyover bridge curving left that will take you to southbound 71 and shortly be out of the construction area onto divided 6 lane. Stay on 71 south to Harrisonville. Just past Harrisonville take the hwy. 7 exit, go left over 71 to Clinton. In Clinton at the THIRD set of traffic signals, go LEFT on 7.
The Nothern Cherokee Trading Post is on the right a ways past Clinton International Airport, 5-6 miles out of Clinton. It doesn't look like much, boarded up door & windows, campground is behind it.
Hope this helps. See you there! Call if you need anything.